 async function doSomething(){
    console.log('执行doSomething')
    return '执行doSomething'
}
 async function testAsync(){
     console.log('testAsync')
    return   'hello async'
}
async function mainfun(){
    console.log('testStart')
    let v1=await doSomething()
    console.log(v1)
    let v2=await testAsync()
    
    console.log(v2)

}
mainfun()
var promise = new Promise((resolve)=> { console.log("promise start.."); resolve("promise");});//关键点2
promise.then((val)=> console.log(val));
console.log('testend')
/*
testStart
执行doSomething
promise start..
testend
promise  这个不对 先执行doSomething testAsync //<===不对 还是第一次写的是对的 node最新版本为准 v10.14.2
执行doSomething  
testAsync
hello async
*/